This old parish church is one of the most ancient and historic in Ireland. It is situated about one and a half miles east above the town of Warrenpoint. St Conall the Great who lived in the century after St Patrick's death is thought to be the builder of the first Christian church here. He is referred to in the "Annals of the Four Masters" as "Conall, son of Cluain, near Snamh Each, ie the harbour into Cael (Narrow Water) in Ui-Eachach, of Ulaidh." He was of royal lineage being sixth in descent from Caolbha, the one hundredth and 23rd monarch of Ireland and the 47th king of Ulaidh. Caolbha was the common ancestor of the Magenisses of Iveagh and the Mccartens of Kinelarty.

In 564AD St Conall was promoted from Clonallon to the Bishopric of Colraine. He died in 590AD and according to the martyrology of Donegal his festival occurs on the 2nd of April.

Conall was succeeded by St Dallan Forghaill who like Conall was also of royal blood. His father Colla Mac Erc was the great grandson of Colla Uais or "The Noble" the 121st king of Ireland 323AD - 326AD. St Dallan was born in Tullyhaw Cavan at the beginning of the 6th century. His mothers name was Forchella and although baptised Eochaidh he was generally called Dallan Forchella or Forgaill, Dallan because he lost his eyesight ( Dallan in Irish means blind). Dallan was the chief poet of Ireland and it was he who composed the "Amrha" in praise of St Columba.

Clonallon is derived from the Irish "Cluain Dallain" meaning Dallan's meadow. The more ancient name of this townland was Ballynacleragh, the town of the clergy which indicates there must have been an earlier ecclesiastical foundation. The monastic site was thought to have been destroyed by the Vikings during their attacks on Ireland from 795AD to 1014AD. The Annals mention that " AD 925 Murkertagh defeated a large body of Danes at Carlingford Loch two hundred of them being killed."

The pre- reformation Church of Clonallon built after the end of the Viking attacks has disappeared although the porch of the present church with its curious architecture and being of great thickness is believed to have formed part of a Norman tower of an ancient building. Papal taxation in 1306AD mentions that "Clonallon" is valued at 4 marks. An Inquisition of 1657 states "the Church of Clonallon hath walles and timber but ruinated, without dores or windows."

Bibilography

History of the Church of Ireland Vols 2&3 (1933)

William Garletons The Dream of an Antiquarian published by S.E.L.B.

William Fulton: Archaeology of Historic Ireland Module, The Queen’s University at Armagh 1999